1. Field of the Invention
The present invention relates to an optical fiber connector plug protecting cap (hereafter, referred to as protecting cap) for protecting a ferrule end face of an optical fiber connector plug.
2. Description of the Related Art
Hitherto, in case where an optical fiber is fixed to a ferrule attached to an optical fiber connector plug, the optical fiber is bonded/fixed to the optical fiber connector plug by pouring a thermosetting adhesive into the optical fiber connector plug, then inserting the optical fiber whose coating has been peeled over a certain length, and heating/hardening the adhesive by a heater. After the optical fiber has been bonded/fixed, the optical fiber connector plug is used by smoothly polishing a ferrule end face and an optical fiber end face to mirror finish. If the polished faces, of the ferrule and the optical fiber, having been subjected to the polish finish are injured, when the ferrules are oppositely connected each other, an opposed position accuracy is deteriorated, so that a loss becomes large. Therefore, for the purpose of protecting the ferrule end face and the optical fiber end face after the polish finish, there has been known a protecting cap fitting to a tip portion of the optical fiber connector plug and formed by rubber, plastic and the like.
As such a protecting cap, there has been proposed a cap 100 with a strap for an FC type optical fiber connector as shown in FIG. 7A and FIG. 78. Incidentally, FIG. 7A is a sectional view of the cap with a strap according to the prior art, and FIG. 7B a plan view of the same.
In the cap 100 with a strap, a cap portion 101 and a strap portion 102 are integrally molded. The cap portion 101 has an engagement hole 103 engaging with an outer periphery of a plug housing of the FC type optical fiber connector (not shown). The engagement hole 103 has a shape in which its diameter gradually decreases toward a tip of the cap portion 101. The cap portion 101 is mounted so as to cover the ferrule protruding from a tip of the plug housing. Further, in the strap portion 102 molded integrally with the cap portion 101, at its tip portion in a side opposite to the cap portion 101 there is provided a passage hole 104 for the purpose of being mounted to an optical fiber cord of the FC type optical fiber connector, so that it is adapted such that the cap portion 101 itself is not disconnected from the optical fiber cord. As a material for the cap 100 with a strap, polyvinyl chloride and rubber have been used.
However, with the conventional protecting cap, since the cap portion and the strap portion are integrally molded, the cap portion where a comparatively high hardness is demanded and the strap portion where a flexibility in some extent is demanded become the same material, so that there has been a problem that characteristics of any one of the cap portion and the strap portion are sacrificed.
Further, since the conventional cap with a strap is integrally molded in a state having the strap, there is a problem that the number of products obtained in a mold cannot be increased.
In view of the forgoing drawbacks in the conventional art, according to the invention, there is provided an optical fiber connector plug protecting cap whose manufacturing time can be remarkably shortened, whose manufacturing cost can be reduced, and in which an optimum material can be selected for both of the cap portion and the strap portion.
A 1st mode of the invention solving the problem in the conventional art is an optical fiber connector plug protecting cap adapted to be mounted to an optical fiber connector plug comprising an ferrule to which an optical fiber is insertion-mounted and a holding member for holding the ferrule. The optical fiber connector plug comprises a resin-made cap member fitted to a tip opening of the holding member and covering a tip portion of the ferrule in a non-contacting state, and a strap member consisting of an elastic body relatively having more flexibility than the cap member. The cap member is provided with a lock hole for locking one end portion of the strap member in an insertion state. The one end portion of the strap member is provided with an engagement protrusion engaging with the lock hole in a state that the one end portion has been passed through the lock hole to thereby make it engageable, and that an end portion side from the engagement protrusion of the strap member becomes a pinching portion capable of being pinched in order that the engagement protrusion is locked to an outer edge portion of the lock hole.
A 2nd mode of the invention is an optical fiber connector plug protecting cap characterized in that, in the 1st mode, the other end portion of the strap member is provided with a passage hole for passing the optical fiber coated.
A 3rd mode of the invention is an optical fiber connector pug protecting cap characterized in that, in the 1st or 2nd mode, at a side opposite to the end portion side of the engagement protrusion of the strap member there is provided an abutting portion which abuts against the outer edge portion of the lock hole.
A 4th mode of the invention is an optical fiber connector plug protecting cap characterized in that, in any of the 1st-3rd modes, the lock hole is provided in an end portion of the cap member at a side opposite to an insertion side of the ferrule.
A 5th mode of the invention is an optical fiber connector plug protecting cap characterized in that, in the 4th mode, the lock hole is formed in a protrusion portion whose cross-section is smaller than that of the cap member.
A 6th mode of the invention is an optical fiber connector plug protecting cap characterized in that, in any of the 1st-5th modes, at least one surface of the pinching portion is provided with a slip prevention portion.
A 7th mode of the invention is an optical fiber connector plug protecting cap characterized in that, in any of the 1st-6th modes, a thin-walled portion is provided between the pinching portion and the engagement protrusion.
An 8th mode of the invention is an optical fiber connector plug protecting cap characterized in that, in any of the 1st-7th modes, the strap member consists of elastomer or rubber.
A 9th mode of the invention is an optical fiber connector plug protecting cap characterized in that, in any of the 1st-8th modes, the optical fiber connector plug is any of an FC type, an SC type, an LC type and an MU type.
In the invention, since the protecting cap is divided into the cap member and the strap member, an optimum material can be used for each of the cap member and the strap member. Further, it can be use only as the cap member.